A worldwide perspective on large carnivore attacks on humans

Large carnivores have long fascinated human societies and have profound influences on ecosystems. However, their conservation represents one of the greatest challenges of our time, particularly where attacks on humans occur. Where human recreational and/or livelihood activities overlap with large carnivore ranges, conflicts can become particularly serious. Two different scenarios are responsible for such overlap: In some regions of the world, increasing human populations lead to extended encroachment into large carnivore ranges, which are subject to increasing contraction, fragmentation, and degradation. In other regions, human and large carnivore populations are expanding, thus exacerbating conflicts, especially in those areas where these species were extirpated and are now returning. We thus face the problem of learning how to live with species that can pose serious threats to humans. We collected a total of 5,440 large carnivore (Felidae, Canidae, and Ursidae; 12 species) attacks worldwide between 1950 and 2019. The number of reported attacks increased over time, especially in lower-income countries. Most attacks (68%) resulted in human injuries, whereas 32% were fatal. Although attack scenarios varied greatly within and among species, as well as in different areas of the world, factors triggering large carnivore attacks on humans largely depend on the socioeconomic context, with people being at risk mainly during recreational activities in high-income countries and during livelihood activities in low-income countries. The specific combination of local socioeconomic and ecological factors is thus a risky mix triggering large carnivore attacks on humans, whose circumstances and frequencies cannot only be ascribed to the animal species. This also implies that effective measures to reduce large carnivore attacks must also consider the diverse local ecological and social contexts.

press the attack, but readily flees after the person reacts [1]. Unprovoked (but not predatory) attacks mostly occurred in North America and Europe, where the animals involved were highly foodconditioned, which can be considered the real cause of the attack.
Because almost half of the cases collected were predatory or unprovoked, it is worth investigating such cases in detail, to identify the main characteristics and potentially important drivers that might increase the risk of such events. As mentioned in S1 File, of the three large carnivore families under study, felids and canids were the most involved in predatory cases, with 93% (n = 1227) felid attacks and 88% (n = 399) canid attacks recorded being predatory or unprovoked. Instead, bears were rarely involved in this type of encounter (4%, n = 70).

Spatio-temporal patterns
Predatory attacks recorded mainly took place in India (72% of the 1696 cases), followed by Africa (14%; Fig 4). We found high inter-species variation in seasonal trends (Fig A). For most species, months with higher attack frequencies probably represent times when carnivore and human activities overlap the most. For example, predatory attacks by American Ursus americanus and Asiatic Ursus thibetanus black bears were mainly concentrated between May and August, when both bears and people are most active outside. Similar trends were found for coyotes Canis latrans, wolves Canis lupus, cougars Puma concolor and jaguars Panthera onca, although cougar attacks were mainly concentrated in late summer months (June-September). Most lion Panthera leo predations were concentrated between March and May, whereas tiger Panthera tigris attacks occurred almost equally throughout the year, with the highest peak in April. A completely different trend was found for leopards Panthera pardus, whose attacks were concentrated between November and March.
However, when analysing the total number of attacks as a Negative Binomial distributed model for all species over the months, we did not find any statistical difference, being the null model the best one: The data underlying statistical models can be found in S2 Data.
Most species attacked during daytime. Only lion attacks were more frequent at night (Fig B).
Information on temporal patterns of predatory attacks by wolves in India was not available.

Mortality rates and main attack characteristics
As expected, predatory attacks caused considerably more deaths compared to all other scenarios (91% of all deaths recorded). Contrary to our predictions and in contrast to that found in previous studies focusing on predatory attacks on humans in North America [3,4], victims of predatory attacks were mostly adults (70%), if considered all together. Like other attack circumstances, the age of the victim varied depending on the species and the local context. On one hand, victims of cougars, coyotes, wolves and leopards were mainly children (Fig C), which is in line with the above-mentioned previous literature. On the other hand, adults were the main targets of predation by the large felids of Asia and Africa (Fig C). One possible explanation could be that in lower-income countries, especially in those areas where felids have specialized in preying on humans, adults are more likely to be found outdoors in large carnivore habitats while carrying out livelihood activities, and thus represent easy prey, whereas children are probably not entering large carnivore habitats but remain more often in proximity of their houses and villages. This is also supported by the prevalence found in human activities during predatory attacks, which was mainly represented by people working and carryig out livelihood activities (65%). It is also important to note that, even within the same species, age prevalence varies depending on the study area.
Similarly, we found that predatory attacks involved almost equally adults alone (46%) and in groups (44%), whereas children alone were slightly less often attacked (3%) than children in groups (7%). This is probably due to the fact that children are predatory attacks by brown bears Ursus arctos and wolves in India was not available.